Calculus destroying apparatus using feedback from a low pressure echo for positioning

Abstract

A calculus destroying apparatus includes piezoelectric elements constituted by arranging a plurality of piezoelectric elements to have a predetermined shape, thereby constituting a shock wave generating source, a first driver for driving the piezoelectric elements by a high voltage pulse so that a shock wave for calculus destruction having a predetermined focal point pressure distribution is generated from the piezoelectric elements, a second driver for driving at least some of the piezolectric elements by a low voltage pulse so that a low pressure ultrasonic wave having a lower pressure and a wider focal point pressure distribution than those of the shock wave is generalized from the piezoelectric elements, a receiver for receiving an echo of the low pressure ultrsonic wave from inside a patient's body via the piezoelectric elements, and a controller for activating the second driver prior to activation of the first driver, and activating the first driver when the intensity of the echo received by the receiver exceeds a predetermined threshold value.

What is claimed is: 
     
       1. A calculus destroying apparatus comprising: a vibration generating source having a plurality of piezoelectric elements;   first driving means for driving said piezoelectric elements so that a shock wave for calculus destruction having a predetermined focal point pressure distribution is generated from said piezoelectric elements;   second driving means for driving at least some of said piezoelectric elements so that a low pressure ultrasonic wave having a lower pressure and a wider focal point pressure distribution than those of the shock wave is generated from said piezoelectric elements;   receiving means for receiving an echo of the low pressure ultrasonic wave from inside a patient's body via said piezoelectric elements; and control means for activating said second driving means prior to activation of said first driving means, and activating said first driving means when an intensity of the echo received by said receiving means exceeds a predetermined threshold value.   
     
     
       2. An apparatus according to claim 1, wherein said first driving means includes means for driving said piezoelectric elements by a pulse having a comparatively high voltage. 
     
     
       3. An apparatus according to claim 1, wherein said second driving means includes means for driving at least some of said piezoelectric elements by a pulse having a comparatively low voltage. 
     
     
       4. An apparatus according to claim 1, wherein said piezoelectric elements include a plurality of concentrically arranged piezoelectric elements. 
     
     
       5. An apparatus according to claim 4, wherein said second driving means includes means for driving only those piezoelectric elements on an inner peripheral side of said piezoelectric elements so as to generate the low pressure ultrasonic wave having a lower pressure and a wider focal point pressure distribution than those of the shock wave. 
     
     
       6. An apparatus according to claim 4, wherein said second driving means includes means for driving each of said piezoelectric elements with a predetermined time difference so as to generate the low pressure ultrasonic wave having a lower pressure and a wider focal pressure distribution point than those of the shock wave. 
     
     
       7. A calculus destroying apparatus comprising: a vibration generating source having a plurality of piezoelectric elements;   driving means having a first driving mode for driving said piezoelectric elements so that a shock wave for calculus destruction is generated from said piezoelectric elements, and a second driving mode for driving at least some of said piezoelectric elements so that a low pressure ultrasonic wave having a lower pressure and a wider focal point pressure distribution than those of the shock wave is generated from said piezoelectric elements;   receiving means for receiving an echo of the low pressure ultrasonic wave from inside a patient's body via said piezoelectric elements; and   control means for operating said driving means in the second driving mode prior to an operation in the first driving mode, and operating said driving means in the first driving mode when an intensity of the echo received by said receiving means exceeds a predetermined threshold value.   
     
     
       8. An apparatus according to claim 7, wherein said driving means includes means for driving said piezoelectric elements by a pulse having a comparative high voltage in the first driving mode, and driving at least some of said piezoelectric elements by a pulse having a comparatively low voltage in the second driving mode. 
     
     
       9. An apparatus according to claim 7, wherein said driving means includes means for driving at least those piezoelectric elements on an inner peripheral side of said piezoelectric elements, in the second driving mode, so as to generate the low pressure ultrasonic wave having a lower pressure and a wider focal point pressure distribution than those of the shock wave. 
     
     
       10. An apparatus according to claim 7, wherein said driving means includes means for driving each of said piezoelectric elements with a predetermined time difference in the second driving mode so as to generate the low pressure ultrasonic wave having a lower pressure and a wider focal point pressure distribution than those of the shock wave. 
     
     
       11. A calculus destroying apparatus comprising: imaging ultrasonic transmitting/receiving means for transmitting/receiving an imaging ultrasonic wave;   image processing means for obtaining an ultrasonic image in accordance with an ultrasonic echo obtained by said imaging ultrasonic transmitting/receiving means;   a vibration generating source having said imaging ultrasonic transmitting/receiving means therein, constituted by a plurality of piezoelectric elements;   first driving means for driving said piezoelectric elements so that a shock wave for calculus destruction having a predetermined focal point pressure distribution is generated from said piezoelectric elements;   second driving means for driving at least some of said piezoelectric elements so that a low pressure ultrasonic wave having a lower pressure and a wider focal point pressure distribution than those of the shock wave is generated from said piezoelectric elements;   receiving means for receiving an echo of the low pressure ultrasonic wave from inside a patient's body via said piezoelectric elements; and   control means for activating said second driving means prior to activation of said first driving means, and activating said first driving means when an intensity of the echo received by said receiving means exceeds a predetermined threshold value.   
     
     
       12. An apparatus according to claim 11, wherein said first driving means includes means for driving said piezoelectric elements by a pulse having a comparatively high voltage. 
     
     
       13. An apparatus according to claim 11, wherein said second driving means includes means for driving at least some of said piezoelectric elements by a pulse having a comparatively low voltage. 
     
     
       14. An apparatus according to claim 11, wherein said piezoelectric elements include a plurality of concentrically arranged piezoelectric elements. 
     
     
       15. An apparatus according to claim 14, wherein said second driving means includes means for driving only those piezoelectric elements on an inner peripheral side of said piezoelectric elements so as to generate the low pressure ultrasonic wave having a lower pressure and a wider focal point pressure distribution than those of the shock wave. 
     
     
       16. An apparatus according to claim 14, wherein said second driving means includes means for driving each of said piezoelectric elements with a predetermined time difference so as to generate the low pressure ultrasonic wave having a lower pressure and a wider focal pressure distribution point than those of the shock wave.